A (usually pocket-sized) book consisting of everyday expressions and vocabulary in two languages and intended for travellers who wish to communicate with locals while in other countries (or regions in which a different language is spoken)
A phrase book is a book used by people travelling to a foreign country. It has lists of useful words and expressions, together with the translation of each word or expression in the language of that country. We bought a Danish phrase book. A book of foreign language expressions and their translations